Desoldering implement

ABSTRACT

A small, hand-held desoldering tool having a spring-loaded piston carried within a cylindrical body member having a removable nozzle element at one end and being substantially open at the other. The piston has a finger-engaging cocking portion which extends radially outwardly through an elongate slot in the cylindrical body member and which permits axial motion of the piston for cocking and flyback. When in the cocked position, a trigger lever carried externally of the body member holds the piston in its forward position. Moving the trigger lever in one direction releases the piston for its flyback stroke and moving it in the opposite sense forces the piston further forward to eject the nozzle element from the body for cleaning or replacement. A rod member carried by the piston extends forwardly through the nozzle element to clean its bore with each cocking cycle. A reading of the complete specification is recommended for a full understanding of the principles and features of the disclosed tool.

United States Patent 1 3,604,610

[72] Inventor William F r un Primary Examiner-John F. Campbell 14250 Dearborn St., Panorama City, Calif. Assistant Examiner-R. J. Craig 91402 AttorneyDaniel T. Anderson [2]] Appl. No. 11,583

[22] Filed Feb. 16,1970

[45] Patented Sept M1971 ABSTRACT: A small, hand-held desoldering tool having 21 spring-loaded piston carried within a cylindrical body member [54] DESOLDERING IMPLEMENT having a removable nozzle element at one end and being sub- Claims, 9 Drawing Figs stantially open at the other. The piston has a finger-engaging cocking portion which extends radially outwardly through an [52] U-S. Cl elongate l i th n dri l body member and which per- 15/344, 219/234 mits axial motion of the piston for cocking and flyback. When [51] Int. Cl B23 1/00, in h k d i i a tri r l ver carried externally of the B23 5/22 body member holds the piston in its forward position. Moving [50] Field of Search 228/19, 20; the trigger lever i one di i l a the piston for its 15/344; 219/234 flyback stroke and moving it in the opposite sense forces the piston further forward to eject the nozzle element from the [56] References Clted body for cleaning or replacement. A rod member carried by UNITED STATES PATENTS the piston extends forwardly through the nozzle element to 3,1 14,026 12/1963 Fortune 219/234 clean its bore with each cocking cycle. A reading of the 3,337,897 8/1967 Lerner et al. 15/341 complete specification is recommended for a full understand- 3,393,854 7/1968 Fortune 228/20 ing of the principles and features of the disclosed tool.

66 30 e4 8 a0 82 29 I2 78 72 FATENTEU SEP! 41971 SHEET 2 BF 2 William S- Fortune Fig-9 ATTORNEY FIELD OF THE INVENTION tory or hobbyist bench; and although in the cause of brevity and clarity, much of the following discussion and description of examples of the invention are directed theretoward, it is expressly to be understood that the advantages of the invention are equally well manifest in other fields, as indicated above, where such substances are to be removed from a limited or particular portion of an object.

BACKGROUND Of THE INVENTION In the electrical arts as mentioned, it is often desired to desolder an electrical connection such as, for example, a wirewrapped terminal, a wire to circuit-board eyelet, or the like. The removal from the connection, of the molten solder without dropping or spattering it onto the other portions of the equipment is generally essential. Blowing or shaking the molten metal away, is therefore not an acceptable practice; and, in combination with its high-mass density, the high-surface tension associated with the solder makes its removal particularly difficult. Furthermore, the problem is aggravated by the requirement that the solder be removed quickly and without application of cooling means before the mechanical connection such as a wire-wrapped terminal may be taken apart.

Various nonportable central vacuum systems and highly portable and efficient hand-held vacuum-stroke tools have advanced the state of the art and have solved certain aspects of the desoldering problems outlined; however, the former suffer from disadvantages of cost, complexity, lack of versatility, and nonportability while the latter suffer from some disadvantages, to a lesser extent, of cost and complexity, and, in some applications, undesirable recoil due to the flyback action of the piston-cocking shaft-knob assembly during the vacuum stroke. Typically, in these prior art devices the cocking shaft which functions as a connecting rod between the piston and the cocking knob must be relatively massive to be strong enough to cock the piston against a relatively strong loading spring. Also the cooking knob is typically large and soft, and therefore massive, for comfortable repeated cocking cycles by the hand of the operator. These criteria cause the flyback mass to be relatively large compared to the thin-walled cylindrical-housing body; consequently, the outer housing suffers a recoil causing a deflection of the solder inlet tip away from the location of the molten solder.

Another disadvantage of the abrupt flyback of the shaft and knob is that the eye of the operator during the vacuum stroke is typically disposed near thereto in a positioncausing risk of eye injury.

It is, accordingly, an object of the present invention to provide improved desoldering apparatus which is not subject to these and other disadvantages and limitations of the prior art.

It is another object to provide such apparatus which, while providing consistently a high amplitude of impulse airflow, has substantially no exposed flyback portion and a very low inertia associated with the flyback portions thereof causing a negligible deflection of the tool during its vacuum stroke.

It is another object to provide such apparatus which is low in cost and simple, rugged, and reliable in its structure and performance.

It is another object to provide such apparatus in which the operator's hand may be disposed to hold the implement closely to its tip end in pencil-holding fashion, for improved precision use thereof.

It is another object to provide such apparatus which is automatically self-cleaning with each cocking cycle.

SUMMARY OF INVENTION Briefly, these objects are achieved in accordance with the structural aspects of an example of the invention in which a hand-held, finger-operated desoldering implement includes a body-barrel member having a forward, nozzle end and a major central portion having, as a function of displacement along its length, s substantially constant and smooth internal surface configuration. A tip element, of the character to be carried ejectably by its frictional engagement with the forward end of the barrel member is provided and is formed to include a forwardly extending nozzle member and a central duct therethrough for drawing mobile substance into the interiors of the barrel chamber. A piston member is carried within the barrel member in a sliding, air seal relation with its smooth internal surface; and the piston member includes a central, forwardly extending noule-cleaning rod for clearing the duct of foreign matter when the piston member travels fully forwardly in the barrel member. The piston member further includes a rearwardly extending, fingerengageable cocking portion.

A trigger-lever member is carried pivotally by the body-barrel member at a pivot fulcrum disposed rearwardly from its nozzle end and includes a body portion extending forwardly to a tip portion thereof which is contiguous to the nozzle end and is normally disposed radially apart from but displaceable toward the barrel member. The trigger-lever member further includes a piston engaging arm portion which is extendable into the barrel member for holding the piston means in a forward, cocked disposition and is removable laterally from within the barrel member for releasing or triggering the piston member for its flyback, vacuum-stroke action when the tip portion of the trigger-lever member is displaced radially inwardly toward the nozzle portion of the barrel member.

The piston and trigger-lever members and said piston are further adapted to force the piston member further forwardly into a tip-ejecting contact with the tip when the tip portion of the trigger lever member is forcefully displaced laterally away from the nozzle portion of the barrel member.

Further details of these and other novel features and their operation and cooperation as well as additional objects and advantages of the invention will become apparent and be best understood from a consideration of the following description taken in connection with the accompanying drawing which is provided by way of illustrative example only.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is perspective of an example of a desoldering tool constructed in accordance with the principles of the present invention in an uncocked, or unloaded, configuration;

FIG. 2 is a longitudinal sectional view thereof; 7

FIG. 3 is a longitudinal sectional view thereof in a nozzle removal configuration;

FIG. 4 is a bottom, partially cutaway, view thereof in a piston released configuration;

FIG. 5 is a perspective view of the rear, capping element portion thereof;

FIG. 6 is an essentially cross-sectional view illustrating certain operational aspects of the implement; and

FIGS. 7, 8 and 9 are views thereof illustrating alternative structural features of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 4 tural concepts of the invention. In this regard, no attempt is made to show structural details of the apparatus in more detail than in necessary for a fundamental understanding of the invention. The description taken with the drawing will make it apparent to those skilled in the mechanical arts how the several forms of the invention may be embodied in practice. Specifically, the detailed showing is not to be taken as a limitation upon the scope of the invention which is defined by the appended claims forming, along with the drawing, a part of this specification.

In FIG. 1 the example of the vacuum-stroke desoldering tool illustrated includes a substantially cylindrical barrel or body 12; a forward tip element 14 and piston element 16 both carried removably substantially therewithin; a trigger-lever element 18 pivotally carried externally thereon by engagement with a pair of mounting pins 20; and a stop member 22 rotatably carried thereon by engagement with a right circumferential retaining groove 24 formed near the rearward end thereof.

Referring to FIG. 2, the barrel 12 may be seen to consist, in this example, of a unitary molded plastic body having a constant internal diameter for the greater part of its length from its open rearward end 26 to a spring retaining shoulder 28 near its forward end, the shoulder 28 being formed by the transition from the larger diameter major portion 29 to a reduced diameter, nozzle-retaining portion 30. Additional structural aspects of the barrel 12 include: The retaining groove 24 and a radially inwardly tapered end cap receiving portion 32 extending from the retaining channel 24 rearwardly to the end 26 of the barrel; a piston-cocking access slot 34 extending from its forward end 36 to and through the extreme rearward end 26 of the barrel 12; a trigger-lever-receiving slot 38; and a finger-grip contoured reduced diameter portion 40 formed contiguously to the forward end 42 of the barrel 12.

The trigger-lever element 18 is also, in this example, a unitary, molded plastic article and comprises a piston-engaging arm portion 44 having a stop-cap-abutting shoulder 46 formed therein and extending generally rearwardly and inwardly from fulcrum determining, mounting-pin-engaging slots, indicated at 48 and shown in a subsequent figure. The main body portion 50 of the trigger-lever element extends forwardly, and substantially parallel to the barrel 12, so that its forward, tip portion 52 is axially disposed contiguously and in fingertip grippable cooperative relation with the reduced outer-diameter-contoured portion 40 of the barrel 12. symmetrically disposed to either side of the main body portion 50 are a pair of shroud portions 54 which add rigidity to the lightweight molded element and which are formed to contain, at their rearward, barrel-straddling ends, the mounting slots 48 for engaging retentively the mounting pins 20 of the barrel 12.

A small trigger spring 56 is compressively retained about an inwardly directed mounting post 58 molded with the under surface of the trigger-lever body 50. The spring 56 serves 1) to maintain, elastically, a disposition of the piston engagement arm 44 whereby cocking of the piston is permitted and, once cocked, the piston is held in its forward, loaded position; and 2) to permit a vacuum-stroke-producing flyback of the piston when the forward tip portion 52 is pressed inwardly by the operators fingertip toward the shaped portion 40 of the barrel 12. This triggering action compressed, slightly, the trigger spring 56 between the underside of the body portion 50 of the trigger-lever l8 and the barrel 12.

The forward-tip element 14 similarly may be of molded plastic fabrication with a central bore 60 extending axially through a forwardly projecting, small diameter nozzle portion 62 thereof. The tip element includes rearward and forward, barrel-engaging cylindrical surfaces 64, 66 which are axially separated by a reduced diameter midportion 68. A forwardretaining shoulder is formed where the surface 66 joins an enlarged diameter forward potion 70 which mates with and terminates the contoured portion 40 of the barrel l2.

In FIG. 3 it may be seen clearly that when the tip element is forced a short distance forwardly to clear the barrel-engaging surface 66, the reduced-diameter portion 68 permits the operator to remove it the remainder of the way by laterally oscillating it as he pulls it forwardly by his fingertips.

To complete the discussion of FIG. 2, the piston element 16, also one-piece plastic-molded, is seen to include a cylindrical body portion 72 having a piston-ring-retaining groove 74 therein which is formed with a tapered, rearwardly converging surface whereby a captive O-ring 76 is substantially free during forward or cocking motion of the piston but in tight-sliding seal relation with the barrel 12 when traversing rearwardly during the flyback vacuum stroke. Formed forwardly of the piston body portion 72 is a reduced cross section portion 78 about which is disposed, in the annular space between it and the inner cylindrical surface of the portion 29 of the barrel 12, the rear end portion of the main spring 80, the latter being axially compressively retained between the larger diameter body portion 72 of the piston element 16 and the spring-retaining shoulder 28 at the forward end of the barrel 12. In practice the reduced cross section portion 78 has been molded in an essentially cruciform cross section configuration thereby significantly reducing the flyback recoil suffered by the barrel during a vacuum-stroke operation of the assembly. A nozzlebore-cleaning rod 82 extends forwardly centrally from the reduced cross section portion 78 and automatically clears the nozzle bore 60 of foreign matter with each cocking stroke of the piston element 16.

A cocking-plunger portion 84 of the piston element 16 extends rearwardly of its body portion 72 and is terminated by an end element 86 which includes a laterally extending, fingerengageable cocking tab 88. Again the axially extending midportion of the plunger 84 may be molded in a skeletal, cruciform configuration for rigidity with minimum mass.

Referring to FIG. 3, the implement 10 is illustrated in tipelement-removing arrangement. By pivoting the trigger-lever element 18 away from the barrel 12, the bearing end 90 of the arm 44 engages the end 86 of the piston element 16 and forces it forwardly as shown. The forward end of the reduced cross section portion 78 of the piston element in turn abuts the rear face of the tip element 14 and displaces it sufficiently forward whereby its forward, barrel-engaging surface 66 is removed from the barrel 12. It may then be grasped externally by the operators finger tips and further removed for replacement by a new or differently shaped nozzle or for cleaning or lubricating the interior of the barrel cylinder.

In the lever action, just described, of the trigger-lever 18, the pivotal engagement of the slots 48 (of the shroud portions 54) with the mounting pins 20 (of the barrel 12) is apparent and is indicated by the motion arrow 92. It may be noted that when the lever 18 is thusly lifted away from the barrel 12, the trigger spring 56 (FIG. 2) is retained on the post 58 and is carried therewith away from its normal contact with the outer surface of the barrel. In this example, the small spring is never in tension; and, in some embodiments, is a simple leaf element molded integrally with the body of the trigger-lever.

Referring to FIG. 4, an arrangement of the elements is illustrated wherein the piston element 16 is shown being drawn axially rearwardly from its containment within the barrel 12 by moving the cocking tab 88 of the piston end element 86 rearwardly along the length of the cocking access slot 34 and beyond the rearward end 26 of the barrel. Such removal is achieved when desired for the servicing of the mainspring 80, thorough cleaning of the cylinder, or replacement or cleaning of the O-ring 76.

In FIG. 5, the stop member 22 which controls the mode of action of the trigger-lever 18 and the removal or assembly of the piston element 16 is illustrated apart from the remainder of the implement assembly. The stop member is in a form as though cut from essentially a thin-walled hollow cylinder body 93 with a slot 34' removed from its full length and a second major portion removed to form a retaining or piston stop shoulder 94. In addition, a forwardly extending, trigger-lever stop tab 96 is formed by removing trigger-lever clearance portions from either side thereof. Formed about its rear periphery is an inwardly directed retaining flange portion 24 which is of the character to engage rotatably retentively the annular channel 24 of the body 12. Similarly, a detent-engaging protrusion 100 is formed in the rear portion of the stop member 22 for indexing with a detent 100' formed in the barre] 12.

The stop member 22 may be fabricated of metal, however, in practice, it has been molded of plastic. During assembly of the implement 10, the stop member 22 may be applied at any time by pushing it on from the rear and forcing the retaining flange 24 over the tapered end portion 32 of the barrel until it snaps into the retaining channel 24. It may then be rotated to a position to permit the insertion of the piston element 16 through the slot 34'. Once the piston element is emplaced, the stop member 22 may be rotated to a position such that the rear of the slot 34 in the barrel blocked by the piston stop shoulder 94.

With reference now to FIG. 6 in particular: During normal operation of the tool, the detent pair 100, 100' are engaged thereby holding the stop member 22 in the rotational disposition indicated in FIGS. 1, 2. When it is desired to force the piston element forward with the trigger lever 18 as for ejecting the tip element 14, the stop member 22 is rotated in accordance with the motion to remove the engagement of the detent pair 100, 100' and until the trigger-lever stop tab 96 is disposed against the stop 102 on the side of the barrel 12 (FIG. 3). This configuration causes the piston stop shoulder 94 to remain as a stop across the piston access slot 34. When it is desired to unblock the slot 34 (FIG. 4) the stop member 22 is rotated in the opposite sense in accordance with the motion arrow 103 until the trigger-lever stop tab 96 is in contact with the stop 104 formed on the opposite side of the barrel 12.

In normal working operation, the detent pair 100, 100 are engaged, the piston is cocked and the nozzle bore cleaned by pressing the cocking tab 88 fully forwardly past the trigger arm portion 44 which is, by the forward motion of the end 86, pushed outwardly against the force of the trigger spring 56, until the end 86 is past the trigger arm 44 whereupon the trigger spring 56 causes the arm 44 to return inwardly behind the end 86 and retain the piston element forwardly against the compressed mainspring in a cocked configuration. The nozzle tip may than be placed contiguously to the material, e.g., molten solder, to be removed and the tip 52 of the trigger-lever pressed inwardly to cause the piston flyback and the desired vacuum stroke. To cushion the termination of the rearward flyback of the piston element, a shock-absorbing rubber cushion 106 may be disposed between the otherwise contacting portions of the cocking tab 88 and the piston, stop shoulder 94.

Referring to FIGS. 7 and 8, it may be seen that, when desired, the rubber cushion may be in the form of an O-ring 106 compressively retained in the circumferential retaining groove 24. In this latter configuration, the entire stop member 22, of the earlier figures, is omitted from the assembly. It may also be noted that in such arrangement, the O-ring 106 may serve to add a desired amount of circumferential support to the otherwise divided end portions of the barrel 12.

Also illustrated in FIGS. 7 and 8 is a structural cutaway at 108 from the body portion of the piston member 16. The cutaway provides clearance radially for the bearing, tip end portion 90 of the trigger-lever 18. When the tool is stored for extended periods of time and when the trigger-lever spring 56 is in the form of a leaf molded integrally with the body thereof, the relief precludes any nonelastic deformation of the leaf spring due to the long term effect of bending stress upon the plastic material.

' A further modification, presently preferred, illustrated in FIGS. 7 and 8 is a pair of integrally molded finger grip tabs 110, 112 provided at the forward end of the barrel 12 to aid the operator in compressing the mainspring 80 with the rear, movable cocking tab 88.

Also illustrated in FIG. 8 is a small, flat trigger arm-resting portion 114 formed on the otherwise sloped rear end portion of the piston element 16. This provides a discrete dwell area for the tip of the trigger-lever 18 when the implement is in its cocked disposition and urges the trigger lever into an enabling position so that the front end 52 thereof is at least reasonably close to the barrel body and therefore most convenient and ready for use. The sloped portion also provides a greater axial displacement of the piston forwardly by the trigger-lever when it is desired to eject the forward-tip element 14 out of the barrel 12.

In FIG. 9, the trigger-lever-supporting fulcrum pins 116 are shown in engagement with the skirt portion 54 of the triggerlever 18. The pins 116, in this example, are integrally molded with the barrel 12; and, in assembly, the skirt portion 54, with appropriate pin-receiving bores 118 provided therein is emplaced onto the barrel 12 by elastically spreading the skirt portions over the ends of the pins 116.

One further point of structure to be noted in this example is that a small protuberance 120 may be added to the rear, 0- ring-engaging portion of the cocking tab 88 to soften, effectively, the piston-stopping action of the O-ring 106.

There have thus been disclosed and described an example of a desoldering tool which achieves the objects and exhibits the advantages set forth hereinabove.

I claim:

1. Hand-held, finger-operated desoldering implement comprising:

body-barrel member having a forward, nozzle end and a major central portion having, as a function of displacement along its length, a substantially constant and smooth internal surface configuration;

tip element of the character to be carried ejectably by frictional engagement by said forward end of said barrel member, said element being formed to include a forwardly extending nozzle member and a central duct therethrough and communicating to the interior of said barrel member for the travel of mobile substance therethrough;

piston means carried within said barrel member in sliding, air seal relation with said smooth internal surface thereof, said piston means including central, forwardly extending, nozzle bore-cleaning rod means for clearing said duct of foreign matter when said piston means travels fully forwardly in said barrel member, said piston means further including rearwardly extending, finger-engageable cocking means;

trigger-lever means carried pivotally by said body barrel member at a pivot fulcrum disposed rearwardly from said nozzle end thereof, said trigger-lever means including a body portion extending forwardly to a point contiguous to said nozzle end and having a tip portion normally disposed radially apart from but displaceable toward, in piston-release-triggering operation relation, said barrel member, said trigger-lever means further including a piston-engaging arm portion which is extendable laterally into said barrel member for holding said piston means in a forward disposition and which is removable laterally from within said barrel member for releasing said piston means for its flyback, vacuum stroke action when said tip portion of said trigger-lever means is displaced radially inwardly toward said nozzle portion of said barrel member,

said piston and trigger-lever means being further of the character to force said piston means further forwardly into tip-ejecting contact with said tip element when said tip portion of said trigger-lever means is forcefully displaced laterally away from said nozzle portion of said barrel member.

2. The invention according to claim 1 in which said forward, nozzle end of said barrel member includes spring-retaining shoulder means disposed internally thereof contiguously forwardly of said substantially constant and smooth internal surface, and which further includes axially compressible main spring means disposed between said piston means and said spring-retaining means for causing vacuum-stroke-producing flyback action upon rearward release of said piston means.

3. The invention according to claim 2 which further includes trigger-spring means disposed between said triggerlever means and said barrel member for biasing said tip portion of said trigger-level means away from said barrel member and said piston-engaging arm portion inwardly.

4. The invention according to claim 1 in which said piston means further includes a piston body portion from which forwardly extends said bore-cleaning rod means, and a rearwardly extending piston control end means affixed to the rear of said piston body portion and which is engageable by said piston-engaging arm portion of said trigger-lever means for selectively holding said piston means in a forwardly, cocked disposition and urging said piston means against said tip element for said ejecting thereof.

5. The invention according to claim 4 in which said piston control end means further includes a finger-engageable surface portion for urging said piston means into its forwardly, cocked position, and in which the rear portion of said barrel member is formed to define an axially elongated cocking slot for cooperative operation with said finger-engageable surface portion of said piston means.

6. The invention according to claim 5 in which said fingerengageable surface portion comprises a laterally extending tab element disposed radially outwardly through said cocking slot.

7. The invention according to claim 6 in which said barrel member is open-ended at its rearward extremity with said cocking slot and said substantially constant and smooth internal surface extending therethrough and further defining a window slot through said barrel member for communication therethrough of said piston-engaging arm portion with said piston control end means of said piston means.

8. The invention according to claim 7 in which said barrel member is substantially cylindrical and is further of the character to include a retaining channel extending circumferentially about at least substantially a major portion of the outer surface of said barrel member contiguously to said rear extremity thereof.

9. The invention according to claim 8 which further includes a stop ring member of the character to be disposed about said barrel member contiguously to said rear extremity thereof, said stop ring member having inwardly protruding, retaining channel-engaging means for axially securing said stop ring member thereto with rotatable freedom circumferentially about said retaining channel, said stop ring member being peripherally noncontinuous by an opening at least as long as approximately the width of said cocking slot whereby when said stop ring opening is circumferentially in register therewith, said piston means is withdrawable from said barrel member.

10. The invention according to claim 9 in which said stop ring member includes a forward extending trigger-lever-engaging portion which is disposable, by predetermined rotational disposition of said stop ring member, over a portion of said window slot of said barrel member and in which said piston-engaging arm portion of said trigger-lever means includes interference shoulder means which engages said trigger-lever-engaging portion of said stop ring member to limit the intrusion of said arm portion inwardly through said window slot, said stop ring member further including stop ring means for normally effectively closing the rear of said cocking slot for retaining said piston means within said barrel member.

11. The invention according to claim 10 which further includes rotation-locking detent and detent engagement pair means carried by said stop ring member and said barrel member for removably locking said stop ring member against rotation in a disposition whereby said trigger-lever arm portion is limited in its travel into said window slot and said piston means is retained within said barrel member, and which further includes rotation stop means for, in a first case, limiting the rotation of said stop ring member in a disposition to permit the removal of said tip member by said arm portion of said trigger-lever means, and, in a second case, permitting the circumferential registering of said cocking slot with said opening in said stop ring member whereby said piston means may be removed rearwardly from said barrel member. 

1. Hand-held, finger-operated desoldering implement comprising: body-barrel member having a forward, nozzle end and a major central portion having, as a function of displacement along its length, a substantially constant and smooth internal surface configuration; tip element of the character to be carried ejectably by frictional engagement by said forward end of said barrel member, said element being formed to include a forwardly extending nozzle member and a central duct therethrough and communicating to the interior of said barrel member for thE travel of mobile substance therethrough; piston means carried within said barrel member in sliding, air seal relation with said smooth internal surface thereof, said piston means including central, forwardly extending, nozzle bore-cleaning rod means for clearing said duct of foreign matter when said piston means travels fully forwardly in said barrel member, said piston means further including rearwardly extending, finger-engageable cocking means; trigger-lever means carried pivotally by said body barrel member at a pivot fulcrum disposed rearwardly from said nozzle end thereof, said trigger-lever means including a body portion extending forwardly to a point contiguous to said nozzle end and having a tip portion normally disposed radially apart from but displaceable toward, in piston-release-triggering operation relation, said barrel member, said trigger-lever means further including a piston-engaging arm portion which is extendable laterally into said barrel member for holding said piston means in a forward disposition and which is removable laterally from within said barrel member for releasing said piston means for its flyback, vacuum stroke action when said tip portion of said trigger-lever means is displaced radially inwardly toward said nozzle portion of said barrel member, said piston and trigger-lever means being further of the character to force said piston means further forwardly into tip-ejecting contact with said tip element when said tip portion of said trigger-lever means is forcefully displaced laterally away from said nozzle portion of said barrel member.
 2. The invention according to claim 1 in which said forward, nozzle end of said barrel member includes spring-retaining shoulder means disposed internally thereof contiguously forwardly of said substantially constant and smooth internal surface, and which further includes axially compressible main spring means disposed between said piston means and said spring-retaining means for causing vacuum-stroke-producing flyback action upon rearward release of said piston means.
 3. The invention according to claim 2 which further includes trigger-spring means disposed between said trigger-lever means and said barrel member for biasing said tip portion of said trigger-level means away from said barrel member and said piston-engaging arm portion inwardly.
 4. The invention according to claim 1 in which said piston means further includes a piston body portion from which forwardly extends said bore-cleaning rod means, and a rearwardly extending piston control end means affixed to the rear of said piston body portion and which is engageable by said piston-engaging arm portion of said trigger-lever means for selectively holding said piston means in a forwardly, cocked disposition and urging said piston means against said tip element for said ejecting thereof.
 5. The invention according to claim 4 in which said piston control end means further includes a finger-engageable surface portion for urging said piston means into its forwardly, cocked position, and in which the rear portion of said barrel member is formed to define an axially elongated cocking slot for cooperative operation with said finger-engageable surface portion of said piston means.
 6. The invention according to claim 5 in which said finger-engageable surface portion comprises a laterally extending tab element disposed radially outwardly through said cocking slot.
 7. The invention according to claim 6 in which said barrel member is open-ended at its rearward extremity with said cocking slot and said substantially constant and smooth internal surface extending therethrough and further defining a window slot through said barrel member for communication therethrough of said piston-engaging arm portion with said piston control end means of said piston means.
 8. The invention according to claim 7 in which said barrel member is substantially cylindrical and is further of the character to include a retaining channel extending cirCumferentially about at least substantially a major portion of the outer surface of said barrel member contiguously to said rear extremity thereof.
 9. The invention according to claim 8 which further includes a stop ring member of the character to be disposed about said barrel member contiguously to said rear extremity thereof, said stop ring member having inwardly protruding, retaining channel-engaging means for axially securing said stop ring member thereto with rotatable freedom circumferentially about said retaining channel, said stop ring member being peripherally noncontinuous by an opening at least as long as approximately the width of said cocking slot whereby when said stop ring opening is circumferentially in register therewith, said piston means is withdrawable from said barrel member.
 10. The invention according to claim 9 in which said stop ring member includes a forward extending trigger-lever-engaging portion which is disposable, by predetermined rotational disposition of said stop ring member, over a portion of said window slot of said barrel member and in which said piston-engaging arm portion of said trigger-lever means includes interference shoulder means which engages said trigger-lever-engaging portion of said stop ring member to limit the intrusion of said arm portion inwardly through said window slot, said stop ring member further including stop ring means for normally effectively closing the rear of said cocking slot for retaining said piston means within said barrel member.
 11. The invention according to claim 10 which further includes rotation-locking detent and detent engagement pair means carried by said stop ring member and said barrel member for removably locking said stop ring member against rotation in a disposition whereby said trigger-lever arm portion is limited in its travel into said window slot and said piston means is retained within said barrel member, and which further includes rotation stop means for, in a first case, limiting the rotation of said stop ring member in a disposition to permit the removal of said tip member by said arm portion of said trigger-lever means, and, in a second case, permitting the circumferential registering of said cocking slot with said opening in said stop ring member whereby said piston means may be removed rearwardly from said barrel member. 